LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (Eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins

Abstract

Compared to the Western European Alps, the ice extent during the Last Glacial Maximum (LGM) and the subsequent deglaciation history of the Eastern Alps east of the Tauern Window remains less well constrained. Also, considerable discrepancies exist between the mapped LGM ice margin (Ehlers and Gibbard, 2011; van Husen, 2004, 2011) and the ice extent predicted by ice-sheet models (Seguinot et al., 2018). Here we present the first 10Be surface exposures ages from two regions east of the Tauern window (Gurktal and Lavantal Alps), which provide constraints on the LGM ice extent and the deglaciation history (Wölfler et al., 2022). Our results show that the deglaciation of the Gurktal Alps occurred between 16-14 ka, which agrees with the predictions from ice-sheet models and implies that the LGM ice cover was greater than mapped. This finding also supported by our analysis of high-resolution DEMs that revealed glacially streamlined ridges and macroscale glacial striations consistent with modelled ice flow directions (Seguinot et al., 2018). In contrast, the 10Be ages from the Lavantal Alps located farther east are either LGM in age or pre-date the LGM, indicating that these regions were ice-free or only partially covered by LGM ice. Based on these results, our future investigations will aim at obtaining more age data from the Eastern Alps to refine the location of the LGM ice margin and the deglaciation history, which is also crucial for climate-evolution and postglacial-rebound models. ReferencesEhlers J, Gibbard PL, Hughes PD (2011) Quaternary glaciations - Extent and chronology. A closer look. Developments in Quaternary Science 15.Seguinot J., Ivy-Ochs S, Jouvet G, Huss M, Funk M, Preusser F. (2018) Modelling last glacial cycle ice dynamics in the Alps. The Cryosphere 12: 3265–3285.van Husen D. (2004) Quaternary glaciations in Austria. In: Quaternary Glaciations: Extent and Chronology Part I: Europe, Ehlers J, Gibbard PL (eds). Elsevier: London: 1–13.van Husen D (2011) Quaternary Glaciations in Austria. In Quaternary Glaciations – Extent and Chronology: A Closer Look, Ehlers J, Gibbard PL, Hughes PD (eds). 15: 15–28.Wölfler A, Hampel A, Dielforder A, Hetzel R, Glotzbach C (2022) LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins, Journal of Quaternary Science  37: 677-687. https:// doi.org/10.1002/jqs.3399